Table of Nations.
Following the narrative of Noah's Deluge in Genesis 6-9, the redactor gives us one of the Bible's genealogies, this one revealing a partial family tree of Noah, beginning with his three sons (but not their wives, who also were on the Ark) and following the line of descent from Noah's boys down to the peoples whom the book's earliest audiences would have been familiar with.
As Bible stories go, this is one you'd have to do a lot of study to appreciate, and one you'd need to muster a lot of enthusiasm to find interesting. It reminds me in a way of books like Virgil's “The Aeneid,” or Geoffrey of Monmouth's “History of the Kings of Britain.” In both those books, the authors traced their people's ancestry back to antiquity and made historically dubious claims that their people were descended from the Trojans, and therefore much greater than other peoples.
There's a bit of that at work here. The author of Genesis 10 (possibly the Priestly source, given that the chapter is a genealogy) names three sons of Noah: Shem, Ham, and Japheth. Ham, whom Noah cursed in the previous chapter, is named as the father of several nations that figure rather negatively in the history of Israel and Judah, among them Nineveh, Mizrayim (Egypt), the Philistines and the people of Canaan.
Japheth, for his part, is listed as the ancestor of peoples who lived north of the historical borders of Israel and Judah, what we now would call Indo-European; and Shem, of course, is the big one, from whom come all the Semitic races, including the Hebrews, the Assyrians, the Arameans, and a few others.
Chapter 10 relates the familiar story of the Tower of Babel, which comes from the Yahwist source. I've read some scholars have linked the Tower of Babel to the ziggurauts of ancient Sumeria. Some small basis for that association may lie in the Table of Nations, which mentions that Nimrod, son of Cush, son of Ham, became a mighty hunter and established a kingdom that began in Babel, Erech and Accad, all in the land of Shinar, the biblical name for Sumer.
Erech itself is another transliteration of the Sumerian city Uruk, one of the oldest cities ever built, and home to the mythological Gilgamesh. There is also a Sumerian tale about “Enmerkar and the Lord of Aratta,” which also relates how languages became confused. Since Chapter 12 relates how Abram came from the land of Erech, it seems reasonable to assume that the author of this passage drew on a storied tradition held in common with Enmerkar and the Lord of Arrata.”
At one level, the story of the Tower of Babel is etiological in purpose; that is, the Genesis narrative includes the story as a means of explaining where all the different human languages come from. But, given its placement – it comes just after the story of the Deluge, and between the Table of the Nations and the genealogy linking Shem to Abram – the author had a deeper purpose than merely explaining why everyone doesn't speak ancient Hebrew.
So what exactly are we to believe has God so worried that he needs to bust humanity up into a bunch of ethnolingiostic groups? Given that chapters six to nine showed God flooding the entire planet, I would argue that it's outside the bounds of reasonable interpretation to claim that God was wringing his hands over the architectural enterprises of the Sumerians.
What the text does indicate is divine concern that human ambition and accomplishment will be unlimited, if God does not confuse human speech. As the story falls immediately after the genealogy of Ham and Japheth and immediately before the lineage of Shem, the implication is that ethnic division is also a point of this narrative, which we will see more of immediately afterward in Chapter 12, the Yahwist account of the covenant with Abram.